Technical calculations

Linear guide life calculations

Life

When linear guides operate in linear motion while supporting loads, repeated stresses apply on the rolling elements (balls) and raceways (rails), eventually causing scale-like flaking due to material fatigue. The total run distance until this flaking appears is defined as linear guide's "Life".

Rated life

Rated life is a total distance 90% of linear guides reach without flaking when a group of the same guides are run under the same condition. The rated life can be calculated with basic dynamic load rating and the load applied on the guides as follows.

When using linear guides, load calculations are initially needed. It is not easy to calculate the loads during linear motion due to vibrations and shocks, as well as load distribution on the guides. Furthermore, operating environment temperature has large effect on life. When these conditions are taken in consideration, the calculations would be as follows.

L: Rated life (km)

fH: Hardness factor (see Fig-1)

fT: Temperature factor (see Fig-2)

fC: Contact factor (see Table-1)

fW: Load factor (see Table-2)

C: Basic dynamic load rating (N)

P: Applicable load (N)

Hardness factor (fH)

In using linear guides, the shaft that balls contact must have sufficient hardness, If adequate hardness cannot be obtained, load rating decreases and life will be reduced as a result. Please compensate the life value with the hardness factor.

Temperature factor (fT)

When the temperature of linear guides exceed 100℃, hardness of blocks and rails will be reduced, causing reduction of life. Please compensate the life rating with temperature factor. * Please use linear guides within the resistant temperature range on product pages.

Contact factor (fC)

Table-1. Contact factor

Number of blocks installed on one rail and contact factor fC

1

1.00

2

0.81

3

0.72

4

0.66

5

0.61

In general, it is common to use 2 or more blocks on 1 rail. In such case, load applicable on each block would not be uniform due to machining variations. As the result, allowable load rating on each block would vary depending on the number of blocks used per rail. Please compensate the life rating with contact factor shown on Table-1.

Load factor (fW)

Table-2. Load factor

App.condition

fw

No external shocks or vibrations and speed is low 15m/min or less

1.0-1.5

No significant shocks or vibration and med. speed 60m/min or less

1.5-20

External shocks and vibrations exist and the speed is high 60m/min or over

2.0-3.5

When calculating loads applicable on linear guides, other than the weight of the object, inertial force due to motion speeds, moment loads, and variations of each over time must also be obtained accurately. However, accurate calculation would be difficult due to repeated starts and stops and various shocks and vibrations. Therefore, the Load Factors shown in Table-2 are used to simplify the life calculations.

Applicable load calculation method

When moment loads apply a block, use the following formula to convert the moment load to applicable load.

Technical calculations

■Lead screw・Lead screw nut selection steps

In order to verify contact surface pressure and sliding speed not to cause abnormal wear on the lead screw nut, obtain surface contact pressure P and sliding speed V. Plot the calculated P and V values against the PV value graph and confirm the intersection. If the intersection falls inside of line ① and ②, it is determined that abnormal wear would not occur.

The rail of the linear guide is made to move to enable wide block spacing placed horizontally.

IDEA NOTE Horizontal leveling

There are 3 leveling bolts to level the engraving surface.

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accessing to the MISUMI site.

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You may be required to separately agree to third party's policies if you use third party software to create or browse the Data or use a third party’s CAD data. In this case, the Company does not assume any responsibility for defects of such CAD data or the software of the third party or violation of their rights. Understand them before use.

CAD Data Limitations

Assembly data shows the assembly drawings in the concept design phase. The sole purpose of the data is to explain the structure and functionality of the assembly and is not considered nor to be used as a final design.
You will need to edit the Data so that it meets your specific design conditions.

Unit assembly Data consists of some sub-assemblies.
It is configured so that each sub-assembly unit can be used as it is or edited.

* The part in the frame is a sub-assembly unit.

The Data for fabricated parts is based on easy-to-edit dimensions and shapes in sketches and histories.

* Unit assembly Data consists of some sub-assemblies.
It is configured so that each sub-assembly unit can be used as it is or edited.

Application Overview

Purpose

Purpose

Adjust workpiece height during engraving process.

Operation

First loosen the lead screw by unlocking the lead screw clamp mounted behind the position indicator. Adjust the height of the workpiece by rotating the hand crank wheel at the end. A vertical scale is mounted beside the lead screw support to provide height adjustments, lock the lead screw clamp again to maintain position.

The part list above only contains MISUMI parts.
Part list download (CSV) includes MISUMI and third party components used in this example.

For price and shipping date see the Web Order System.

TERMS AND CONDITIONS FOR USE OF CAD DATA

Your access to the CAD data that MISUMI Corporation (hereinafter referred to as the Company) posts on this site (including 3D CAD data, intermediate 3D CAD data and 2D CAD data; hereinafter referred to as the Data) are of products manufactured and/or sold by the Company (hereinafter referred to as the Products) assumes that you have read and accepted these terms and conditions which govern your use of the Data. If you do not agree to these terms and conditions, you must stop using this website and the Data. You must not use the Data for any unlawful purpose or in any manner inconsistent with these terms and conditions.

1. CAD Data

The Data is prepared for assisting the Company's users in the CAD design process by providing dimensions and other Product information. In order to provide the best speed and stability working within this site, the Product drawings were simplified to reduce the size of the Data. For instance, some of the Products are shown without the oil groove shape, screws or spring shape. Also, please be aware that the tolerance, surface roughness and/or chamfer of the Data may vary from the actual Products.

2. Disclaimer on Data

While the Company has carefully prepared the Data, accuracy of the Data is not guaranteed and is subject to the variances as described above. The Company may also modify, add or delete the Data at any time without prior notice. The Company assumes no liability for any direct, indirect, consequential or special damages that you may claim resulted from your use of the Data or any changes to or deletions of the Data regardless of the reason. The Company provides no warranty as to the quality, accuracy, functionality, safety or reliability of the combination of Products and parts. Example applications and combinations of the Products are provided for illustrative purposes only.

3. Copyright

Copyrights to the content and the Data belong to the Company or the manufacturers of the Products. The said copyright is protected by the Copyright Act and international treaties. The use (including duplication, modification, uploading, posting, transmission, distribution, licensing, sales and publishing) of the Data except for the purpose to use the Data described above without prior approval of the Company is not allowed. The Data cannot be used for any purposes (including sales promotion) except for designing your machine. If you violate this provision or the laws or regulations, the Company may prohibit you from the use of the Data, the Company’s site and/or take legal action. So long as you comply with these terms and conditions, the Company grants to you a non-exclusive, non-transferable, revocable license to access and use the Data for the sole purpose of assisting you in designing machines that incorporate products.
In case that the CAD data is found to
have been to be used for any purpose other than mentioned above or
against the related laws, MISUMI may take legal actions, including
the one for blocking the involved user from using CAD data and from
accessing to the MISUMI site.

4. Disclaimer of Warranty

ANY AND ALL CONTENT APPEARING ON THIS WEB SITE IS PROVIDED FOR INFORMATIONAL PURPOSES ONLY. THIS WEB SITE, ITS CONTENT AND ITS LINKS ARE PROVIDED ON AN "AS IS" AND "AS AVAILABLE" BASIS AND ARE USED ONLY AT YOUR SOLE RISK, TO THE FULLEST EXTENT PERMISSIBLE BY LAW. THE COMPANY DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, OF ANY KIND, REGARDING THIS WEB SITE (INCLUDING ITS CONTENT, HARDWARE, SOFTWARE AND LINKS), INCLUDING AS TO FITNESS FOR A PARTICULAR PURPOSE, MERCHANTABILITY, TITLE, NON INFRINGEMENT, RESULTS, ACCURACY, COMPLETENESS, ACCESSIBILITY, COMPATIBILITY, SECURITY AND FREEDOM FROM COMPUTER VIRUS. THE COMPANY WILL NOT BE LIABLE FOR ANY DAMAGES OR LOSSES, INCLUDING DIRECT, INDIRECT, CONSEQUENTIAL, SPECIAL, INCIDENTAL OR PUNITIVE DAMAGES AND/OR LOST PROFITS, IN CONNECTION WITH USE OF THE INTERNET, THIS WEB SITE, ITS CONTENT OR ITS LINKS Further, the Company will not be liable to you for any failure or delay by the Company to provide access to the Data or any of its obligations under these terms and conditions where such failure or delay is the direct or indirect result of any circumstances beyond the Company's reasonable control (and the Company's obligations will be suspended for the duration of such circumstances).

5. Policy of Third Parties

You may be required to separately agree to third party's policies if you use third party software to create or browse the Data or use a third party’s CAD data. In this case, the Company does not assume any responsibility for defects of such CAD data or the software of the third party or violation of their rights. Understand them before use.

CAD Data Limitations

Assembly data shows the assembly drawings in the concept design phase. The sole purpose of the data is to explain the structure and functionality of the assembly and is not considered nor to be used as a final design.
You will need to edit the Data so that it meets your specific design conditions.

Unit assembly Data consists of some sub-assemblies.
It is configured so that each sub-assembly unit can be used as it is or edited.

* The part in the frame is a sub-assembly unit.

The Data for fabricated parts is based on easy-to-edit dimensions and shapes in sketches and histories.